Abstract:

In this paper, we present a Fluid Stochastic Petri Net
(FSPN) based model which captures the behavior of aging
software systems with checkpointing, rejuvenation and
self-restoration, three well known techniques of software
fault tolerance. The proposed FSPN based modeling framework
is novel in many aspects. First, the FSPN formalism is
extended by adding flush-out arcs. Second, the three
techniques are simultaneously captured in a single model for
the first time. Third, the formalism enables modeling
dependencies of the three techniques on various system
features such as failure, load and time in the same
framework. Further, our base FSPN model can be viewed as a
generalization of most previous models in the literature. To
demonstrate, we present a set of FSPNs which are simple
modifications of the base model. These represent software
systems with checkpointing only, rejuvenation only and
checkpointing and rejuvenation. We show that these FSPNs can
not only mimic previously published models but can also
extend them. For one FSPN model, we present numerical
results to illustrate their usage in deriving measures of
interest.